figure



July 10, 1962 H. w. scHNElDl-:R ETAL 3,043,991

STOP MOTION DEVICE AND CONTROL CIRCUIT THEREF'OR Filed July 10, 1959STOP MTiON DEVICE AND CONTROL CIRCUIT THEREFOR Henri W. Schneider andAlbert C. Leenhouts, Enschede, Netherlands, assignors to J. F. Scholtenand Zonen, N .V., Willemstad, Curacao, Netherlands, a corporation ofCuracao, Netherlands Antilles Filed July 10, 1959, Ser. No. 826,285 12.Claims (Cl. 317-130) Thisinvention relates to teXtile apparatus andmore particularly to a photoelectrically operated stop motion device andcontrol circuit for detecting broken or slack strands of textilematerial in textile machinery such as roving frames, spinning frames,and the like.

In the production of textile material such as yarn and the like, manyOperations are required for the processing of textile fibers such ascotton, wool and the like into yarn. In many of these Operations, thefibrous textile material is processed while in the form of a continuousstrand utilizing various textile apparatus such as drafting frarnes,roving frames, spinning frames, land the like.

. These continuous strands of fibers processed in such apparatus aregenerally relatively thin, delicate, and easily broken. F or instance,in the roving operation carried out on roving frames, a plurality ofindividual strands or sliver, each of which are composed of a looseassembly of textile fibers are drawn to a smaller diameter and twistedinto roving so that alignment of the fibers is obtained and the strandsare reduced to a diameter more suitable for subsequent Operations suchas spinning.

As is well known, textile machines such as roving frames are arranged toprocess -a plurality of such strands simultaneously and in order to moreeconomically utilize space, the strand processing stations or '*spindles'are arranged in closely spaced relationship on each frame. Forinstance, it is not uncommon to provide for simultaneously processing upto 150 strands and more on a single roving frame depending, of course,on the type and size of the frame employed.

As a result of its thin, delicate state, the roving often 'breaks duringthe roving operation and if the roving frame is not stopped immediately,many difificulties are presented. One effect of a break in a strand ofroving is the winding or lapping of a broken end of roving about one ofthe upper drafting rolls and thereby produce an increase in the spacingof the drafting rolls. This increase in roll spacing is generallycarried over to adjacent rolls which are interconnected thereto so thatthe diameter of the adjacent strands of roving quickly increases.Sub'sequently, unless the frame is immediately stopped, the adjacentstrands of roving become entangled with resultant damage to the rolls,flyer, and frame from the jamming of the roving frame and its associatedparts due to the heavy accumulated mass of textile material. In anothersituation, the broken end of the roving is fiipped about across adjacentstrands of roving so that considerable damage to the frame will resultas discussedV above unless the roving frame is stopped immediately. Thisentanglement between roving strands on a frame may also occur when anend becomes excessively slack and therefore whips about to catch andbecomes entangled with the adj acent strands of roving.

Various mechanisms have been proposed for detectng a break in strands oftextile material such as roving and for shutting down the textile frameby deenergizing the frame drive means or motor when such a break isdetected. These mechanisms are generally referred to as stop motiondevices and are generally of the mechanical type in that they depend oncontact with the strand being monitored in order to function. Thisrubbing contact with the strand or textile material common to themelited States Patent O 3,043,991 Patented July 10, 1962 lCC chanicaltype of stop motion device is preferably avoided and the need has beenlong present for a suitable stop motion device which avoids suchcontact.

For instance, in one type of mechanical stop motion device, the rovingadvances through an eye in continuous contact therewith and 'as a resultof its fragile' nature, the roving is not unaifected by this rubbingcontact. The likelihood of damage or alteration to the roving is evenmore pronounced in roving formed from Synthetic material than in rovingformed from natural fibers. Synthetic fibers readily slip`relative toeach other and therefore are easily disturbed by such contact with theeye of the stop motion device. In addition, the roving must berethreaded through this eye after each break.

Furthermore, all moving mechanical devices are subject to Wear throughuse and maintenance is always a problem. Even with proper maintenance,however, mechanically operated devices =are always subject tomalfuctioning and in an installation such as a textile mill or the like,the excessive dust and lint which accumulates on such mechanical stopmotion devices materially increases the likelihood of malfunctioning andthe need for more frequent maintenance.

Accordingly, 'a primary object of this invention is to provide a new andnovel stop motion device and control circuit for textile machineryarranged to process strands 'of textile material which respondsinstantly and without fail to initiate a shutdown of the machine uponthe breaking or slackening of a strand.=

A further object of the invention is to provide a new 'and novel stopmotion device and control circuit for textile apparatus which utilizes aphotoelectric strand scanning or monitoring arrangement for detectingand signaling broken or slack strands of textile material and whichelirninates rubbing contact with the strand.

Another object of the invention is to provide a new and novel stopmotion device and control circuit for initiating an interruption in theadvance of a strand of textile material such as roving upon the breakingor slackening of the roving and which is provided with timing means vfordelaying the initiating action until 'the lapse of a predeterrninedinterval of time.

Still another object of the invention is to provide a new and novel stopmotion device for textile apparatus which is inexpensive to manufacture,small and compact so as to permit easy linstallation adjacent a strandof textile material on presently existing teXtile frames, which iscapable of highly reliable, prolonged use Without breakdown and whichresults in increased production with an attendant reduction inmanufacturing costs.

A still further object of the invention is to provide a new and novelcontrol circuit for a stop motion device employed on textile apparatuswhich utilizes a minimum number of readily available electricalcomponents of the type which do not require critical adjustrnent and inwhich the components may be readily miniaturized so as to permit compactassembly.

Still another object of the invention is to provide a new and novelcontrol circuit for an electrically operated stop motion device whichquickly deenergizes the driving means in a teXtile frame used to processa plurality of strands of teX-tile material upon the occurrence of abreak or slack in any one of the strands.

Another object of the invention is to provide a new and novel method ofdetecting a 'broken or slackened condition in advancing strands oftextile material and instantly in'terrupting the advance of suchstrands.

Briefly, the objects of the invention and other related objects areaccomplished by providing a housing in which is located a portion of thecontrol circuit of the invention. The housing is small and compact so asto be readily mounted on a -textile frame adjacent a strand of textilematerial such as roving and is provided with a slot through which thetextile material is continuously advanced by any suitable means on theteXtile frame. Photoelectric control means are associated with the slotwhich scans the strand of textile material to signal the absence of thestrand from a predetermined zone in the slot resulting from a break or aslackened condition in the strand and to interrupt the advance of thestrand. In order to interrupt the advance of the strand, the controlCircuit of the invention contains a relay device for performing acontrol function such as the deenergizing of the drive motor of vthetextile frame. Means are provided in the Circuit for producing controlvoltage which inoperatively conditions the relay device. The Circuitalso includes an electron discharge which when conductive operativelyconditions the relay device so that the control function is perfortned.The photoelectric control means are included in the Circuit and cutoifthe electron discharge device during normal advance of the strand in theslot zone. When the strand or roving is absent from the zone in theslot, the photoelectric control means permits the electron dischargedevice to conduct and the control voltage is increased sufiiciently topermit the relay device to be operatvely conditioned and the advance ofthe broken strand is interrupted.

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds when taken in connection withthe accompanying drawings, in which- 'FIGURE 1 is a side view of aportion of a textile frarne illustrating the mounting of a stop motiondevice constructed in accordance with the invention;

FIGURE 2 is a front view of the apparatus of FIG- URE 1; and

FIGURE 3 is a schematic wiring diagram of a control Circuit inaccordance with the invention utilized in the stop motion device of`FIGURES 1, 2 and illustrating by means of dotted lines the division ofthe control circuit into two portions.

Referring to the drawings and to FIGURE 1 in particular, there is showna portion vof a teXtile apparatus with which a stop motion deviceconstructed in accordance with the invention is incorporated. Theparticular textile apparatus lwith which this invention lis incorporatedis a roving frame of any 'well known type which is arranged to process aplurality of strands or ends of sliver into roving.

As is well known, a roving frame is provided with two or more pairs ofdrafting rolls 11 between which a strand of textile fibers such as asliver is drawn for fiber alignrnent and reduction in strand diameter.This strand of textile material emerging from the front pair of rolls 11advances into a rotating flyer 12 which twists the drafted strand intoroving 13 and winds the roving onto a holder or bobbin 14 to form aroving package 16.

As has been explained above, the roving 13 is still an elongated bundleof relatively short teXtile fibers with relatively little twist andfrequently breaks or goes slack at some point between the drafting rollsii and fiyer 12. This breaking or slackenng disrupts the rovingoperation and produces doubling with adjacent ends of roving to causedamage to the rolls, flyers and frame unless the frame is quicklystopped as explained above. Means have been provided therefore with thisinvention for electrically monitoring or scanning each strand of roving13 without contacting the roving to immediately shutdown the frame suchas 'by deenergizing its drive motor when a break or slackened conditionin the roving occurs.

More specifically, the stop motion device of the invention com-.prises ahousing 17 adjustably positioned in any suitable manner such as bybrackets 18, 19 on a rigid member 21 of a roving frame. The housing 17is arranged to contain a portion of the control circuit of the invention(FIGURE 3) and may lbe adjustably positioned so that it may properlymonitor a single strand of roving 13 as it is advanced.

The housing 17 is provided witr a recess or slot 27,, preferablysubstantially U-snaped which extends across the housing at one end so asto accommodate the roving 13 as shown in FIGURES 1, 2. Although thehousing 17 may be mounted in any suitable position, it is preferablymounted, as shown, in a position v/herein the slot 2,2 opens laterallyacross the path of the advancing roving 13. In this position of thehousing, the substantially parallel side walls 23, 24 of the slot 22prevent the roving from being moved out of the slot by the oscillationsof the roving which occur in a substantially Vertical d' 'ection as theroving advances toward the fiyer T2.

In order to sense the presence of yarn in the slot 22, photoelectriccontrol means are associated with the slot 22 for determining thepresence of the roving withii'i a predetermined zone in the slot. Morespeeifically, the slot side wall 23 contains a light source or lamp 26and slot side wall 24, a photoelectric control device or light sensitivecell 27 which is responsive to the light beam emanating from the lightsource 26. The light source 26 therefore projects a light beam whichdefines a predetermined strand control zone within the slot 22 so thatif the roving breaks or goes slack, the control Circuit acts to performa control function such as deenergizing the drive motor of the rovingframe as will be explained hereinafter.

Referring now to FIGURE 3, there is shown a control Circuit Constructedin accordance with the invention which is incorporated within the stopmotion device of Vthe invention. The Circuit of FIGURE 3 has beendivided into two portions each shown enclosed within dotted lines anddesignated broadly by the numerals 31, 32.

The portion of the Circuit which will hereinafter be referred to as thedetector unit and which is identified by the numeral 31 is that portionof the Circuit which is preferably positioned within the housing 17 andincludes the light source 26 and the photoelectric control device 27.The portion of the Circuit hereinafter referred to as the power andrelay unit and which is shown within the dotted lines 32 is preferablyconnected to a plurality of lthe detector units 31. One detector unit 31is used for each strand of roving 13 being processed on the frame andtherefore a plurality of such detecting units 31 are arranged inparallel for connection to a single power and relay unit 32.

The power and relay unit 32 is connected to the suitable source of power(not shown) 'by means of conductors 33 connected to the primary windingof a transformer designated generally by the numeral 34-. Thetransformer 34 contains a secondary winding 36 grounded at one end bymeans of conductor 37 and having a tap 38 associated therewith forproducing a control voltage.

This control voltage is produced by rectifying the A.C. voltage obtainedfrom the transformer secondary tap 38 in a rectifier 39 having a filtercapacitor 41. associated therewith. This control voltage is then appliedby means of ccnductor 42 and serially connected resistors 43, 44 to acontrol electrode or grid 45 of an electron discharge device employed asa relay device for initiating the performance of a control function. Inthe specific em- 'bodiment illustrated the relay device 4-5 comprises agasfilled electron tube or thyratron having an anode or plate 47. Acapacitor 43 one side of which is grounded is preferably connected alsoto the control electrode In practice, it has been found that a controlvoltage of approximately 8 volts DC. is satisfactory. For a purpose tobe explained hereinafter, this D.C. control voltage will contain a smallA.C. component or ripple due rto the presence of hum and a filter chokewas therefore left out purposely.

In order to provide a source of power for the thyratron 4a, a rectifier49 is connected by means of Conductor 51 to the other end of thetransformer secondary coil 36. The rectifier fi? thercfore provides asource of positive D.C. voltage and has its load side connected by meansof condnctor 52 through a manual push button switch 53 and a relay coil54 to the thyratron plate 47.

VA filter capacitor 55 is preferably also connected to the load side ofthe rectifier 49 for reducing the ripple in voltage. A switch 56 isassociated with the relay coil 54 and is arranged to be moved therebybetween the solid and dotted line positions of FIGURE 3.

It can be 'seen that in the solid line position of FIGURE 3, switch 56is arranged to connect a source of power (not shown) to a drive motor 57employed as the driving means for the ro'ving frame.

The negative DC. control voltage from rectifier 39 which is applied tothe thyratron grid 45 is of a value to normally maintain the thyratron'46 non-conductive as the drop in the control voltage across resistors43, 44 is negligible due to the small current fiow. If desired, apositive bias voltage is also applied to the thyratron grid 45 through avoltage divider network comprising resistors 58, 59, 60 which isovercome by the negative control voltage when' the thyratron is cut-off.

In order to interconnect the power and relay unit 32 with the detectorunits 31, condnctor 61 is connected to the junction of condnctor 42 andresistor 43 and applies the negative control voltage to the base 62 ofan electron discharge device or transistor 63 through a resistor 64. Theconductor 61 is also connected to one side of a resistor 66 and to oneside of the light source 26, the other side of which is grounded bymeans of ground condnctor 67.

The transistor 63 contains an emitter 68 connected to the groundcondnctor 67 and a collector 69 connected by means of condnctor 71 tothe junction of resistors 43, 44. The transistor 63 is of the type whichwill conduct when its base 62 has a negative voltage applied thereto andconversely will be cut-off when the negative base voltage is removed orreduced to a' predetermined level.

The photoelectric control means of the circuit is arranged to controlthe actuation of the transistor 63 and consequently the value of thecontrol voltage applied to the base 62 of transistor 63. Morespecifically, the other side of resistor 66 is connected to one side ofthe photoelectric control device 27 which in the specific enibodimentillustrated comprises a phototransistor and to the base 62 of transistor63 through a voltage doubling circuit comprising a pair of capacitors72, 73 and a pair of rectifiers or diodes 74, 76 and Va resistor 77. Thevoltage doubling circuit is arranged in the conventional manner,

as shown, :with one side of capacitor 72 and diode 7 6 connected to theground condnctor 67. This voltage doubling circuit will, of course, notpass the D.C. component of the control voltage but rectifies any A.C.voltage fed thereto as well as increasing its magnitude and reversingits polarity so that a positive D.C. voltage will be applied to lthetransistor base 62. As will be explained hereinafter, this A.C. voltageapplied to the voltage doubling circuit may be either the A.C. componentof the negative DC. control voltage zor it may be derived fromfiuctuations in the current fiowing through the phototransistor 27.

In the specific embodiment illustrated, the phototransistor 27 isprovided with a base 78, 'an emitter 79 and a collector 81 which isconnected to the junction of capacitor 73 and resistor 66. Apotentiometer 82 is connected across the base 7-8 and emitter 79 of thephototransistor and is provided with a movable tap 83 connected to theground condnctor 67. It should be understood that the sensitivity of thephototransistor can be adjusted by means of the movable tap 83associated vvith potentiometer 82. The phototransistor 27 is of the typewhich is cut-off in the absence of light on its base 78 i.e. when astrand of textile material is present between the light source 26 andthe phototransistor base 78 in a predetermined zone in the housing slot22 so as to interrupt the light beam emanating from the light source 26.

In the operation of the control circuit of the invention, the presenceof a strand in the predetermined zone in the housing slot 22 (FIGURE 1)interrupts the light beam em'anating from the light source 26 and thephototransistor base 78 is substantially dark so that thephototransistor does not conduct to any apprecialble degree.

In most instances, the irregularities in the diameter of the strandand/or the oscillations of the strand as it advances produces 'a smallvarying current flow through the phototransistor 27 which is suficientto feed an A.C. voltage into the voltage doubling circuit which isrectified and magnified as explained above. Even if the strand is veryeven and moves along a fixed path without oscillations, the highresistance of the phototransistor permits the A.C. component of the D.C.control voltage to be 'applied to the voltage doubling circuit in thedetector unit 31. Thus, when the strand is advancing properly a positiveD.C. voltage is always applied to the base 62 of transistor 63 inopposition to the negative voltage being simultaneously applied to thetransistor base 62 through resistor 64. The values of the electricalcomponents and of the applied voltages have been selected so that whenthe negative control voltage is reduced to a predetermined level oreliminated by the positive voltage produced by the voltage doublingcircuit, the transistor 63 is cut-otf and no current fiows in condnctor71. The control voltage applied to the thyratron grid 45 throughresistors'43, 44 i-s thus of sufiicient magnitude to prevent thethyratron from igniting as explained above.

When the strand of roving leaves the predetermined zone in the housingslot 22 as a result of a break or slackened condition in the strand, thelight beam from light source 26 falls on the phototransistor base 78 andthe phototransistor conducts. When the phototransistor 27 conducts alarge current fiows through the resistor 66 and the phototransistor sothat an A.C. voltage is no longer applied to the voltage doulblingcircuit and the base 62 of transistor 63 has applied thereto only thenegative D.C. control voltage through the resistor 64.

When its base goes negative, transistor 63 conducts and a large currentfiows through condnctor 71. As a result of this current fiow, asubstantial voltage drop occurs across the resistor 43 in 'the power andrelay unit 32 to thereby increase the voltage of the thyratron grid 45to `a level whereat the thyratron 46 will conduct. It has been found inpractice, 'that where a D.C. control voltage of 8 volts 'has beenemployed and resistor 43 has a value of approximately 4700 ohms, avoltage drop of approximately four (4) volts 'across resistor 43 issufficient to ignite the thyratron. The voltage divider circuitcomprising resistors 58, 59 and 60 applies a small positive voltagecontinuously to the thyratron grid 45 as has been explained above toinsure that ignition of the thyratron will take place when the voltage'applied to the thyratron grid is'increased.

It is thus seen that, when light of sufiicient intensity impinges uponphototransistor 27 to cause transistor 63 to conduct, the controlvoltage on `grid 45 is increased so that grid 45 is less negative andsufficiently increases the flow of current between the cathode 'and theplate 47 to cause the thyratron 46 to conduct. The relay coil 54 is thenenergized and actuated so that, under its attractive force, the switchor contactor 56 is moved from the solid line to the dotted line positionof FIGURE 3, opening the circuit to the drive motor 57 of the rovingframe and halting the advance of the roving. As can be seen, when thecontactor 56 moves to the dotted line position of FIGURE 3, one side -ofthe coil 54 is connected to ground through conductors 85, 86 so as tokeep the coil 54 energized even though the thyratron 46 may beextinguished.

In order to deenergze the thyratron 46 and permit the contactor 56 toreturn to the solid line position of FIG- URE 3 wherein the rovingfr-arne drive motor 57 is energized, the push bfutton switch 53 isdepressed to open aeaaaai f 'i' the Circuit from the rectifier 49 andthereby remove the voltage from the thyratron plate 47. When the pushbutton returns to its normally closed position, the above describedstrand monitoring operation of the stop motion device is resumed.

A signal light 37 as shown in FIGURE 3 is preferably employed forindiCat-ing the connection of the stop motion device to a source ofpower. In the circuit of FIG- URE 3, the signal light 37 is connected atone side to conductor 38 and at its other side through the thyratronfilarnent conductors '88 `and |a resistor 89 to the ground conductor 37.

The time Constant for circuit operation i.e. the rate at which thepositive D.C. voltage produced by the voltage doubling circuit drops orfalls off after the phototransistor Conducts, is determined by 'thevalues of condenser 72 and resistors 64, 77. The delay therefore betweenthe detection of a break or Slack condition in the roving and theconducting of transistor 63 to initi-ate interruption of the rovingadvance may therefore be readily determined by the selection ofappropriate values for these three components. It has been found inpractice |that a delay of approximately three seconds gives satisfactoryoperation and such dciay is preferably not reduced substantially belowthis three second time interval.

it Can be seen that there has been provided with this invention anelectrically operated stop motion device for textile machinery such as aroving frame in which a strand of textile material or roving may beadvanced while being monitored or scanned completely free from contactwith any mechanical device. By the use of a photoelectric strandscanning device, a break or slack Condition in the roving may beimmediately detected and through the novel control circuit employed Withthe stop motion device the roving frame is instantly shut down to haltthe advance of the roving and prevent damage to the roving frame. Thestop motion device of the invention may be employed on any type ofteXtile machinery and Will monitor any size strand of teXtile materialwithin a wide range. The problems heretofore encountered with the use ofmechanical type of stop motion device such as mechanical failure, theneed for periodic maintenance and replacement of parts, and therelatively short life of the working parts are no longer of any concernand the device of the invention may be manufactured inexpensively usingreadily available Components.

Another outstanding feature of the invention is the case with which thestop motion device may be installed on conventional textile machinery ina minimum of space so that presently existing units may be readilyadapted for use with the stop motion device of the invention.

in the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation, the scope of the invention being defined in theclairns.

We claim:

l. An electrical control circuit for a stop motion device comprising, incombination, a gas filled electron tube having a control electrode forinitating an interruption in the advance of a strand of textilematerial, means for producing a control voltage, means for applying saidcontrol voltage to said control electrode and preventing ignition ofsaid electron tube, an electron discharge device arranged to conduct andraise the control Voltage applied to said control electrode Whereby saidelectron tube is ignited, means for applying said control voltage tosaid electron discharge device and biasing said electron dischargedevice non-conductive, photoelectric control means in said controlcircuit responsive to the presence of an advancing strand of textilematerial in a predetermined zone for developing a voltage opposing thecontrol voltage applied to said electron dischavrge device and therebyreducing the voltage in said electrode to prevent ignition of saidelectron tube, said photoelectric control means being arranged so thatthe absence of said strand from said predetermined zone causes saidphotoelectric control means to conduct and thereby eliminate saidopposing Voltage to permit said electron clischargc device to conductunder the biasing of said control voltage and thereby to ignite saidtube.

2. An electrical control circuit for a stop motion device in accordancewith claim 1 wherein said control voltage is applied to said controlelectrode through an impedancc and wherein said electron dischargedevice is connected between said impedance and said control electrode toincrease the voltage drop across said impedance when said electrondischarge device conducts.

3. An electrical control circuit for a stop motion device comprising, incombination, a gas filled electron tube having a Control electrode,means connected to said electron tube for initiating an interruption inthe advance of a strand of textile material when said electron tube isconductive, means for produciug a control voltage having an A.C.Component, means including an impedauce for applying said controlvoltage to said control electrode for preventing ignition of saidelectron tube, a transistor having its collector connected between saidimpedance and said control electrode whereby a current flow in saidtransistor produces a voltage drop in said control voltage across saidimpedance and permits said electron tube to ignite, means for applyingsaid control voltage to the base of said transistor to produce a currentilow in said transistor, means for rectifying the A.C. component of saidcontrol voltage `to produce an opposing voltage of opposite polarityfrom the control voltage applied to said transistor base and combinedtherewith to maintain said transistor in a non-conductive condition, aphototransistor, a light source operatively associated with saidphototranstor for defining a strand control zone, said phototransistorbeing arranged to produce a second A.C. voltage from the fiuctuations inthe current flow through said phototransistor produced by theirregularities in the strand diameter and oscillations of said strandadvancing through said strand control zone, said second A.C. voltagebeing also rectified by said rectifying means together with said controlvoltage A.C. component and applied to said transistor base, saidphototransistor being arranged to conduct in the absence of said strandfrom said strand control zone and eliminate said A.C. voltage to permitsaid transistor to conduct and produce ignition of said gas filledelectron tube.

4. An electrical control circuit for a stop motion device comprising, incombination, an electrically opcrated relay device for performing acontrol function, an electron discharge device for Controlling theactuation of said relay device and arranged to Cause actuation of saidrelay device i when conductive, means for producing a control voltagefor inoperatively conditioning said relay device and for operativelyconditioning said electron discharge device, means includingphotoelectric control means in said control circuit responsive to thepresence of an advancing strand of teXtile material in a predeterminedzone for producing a voltage in opposition to the control voltageapplied to said electron discharge device to render it nonconductive,said photoelectric control means being arranged to respond to theabsence of said strand from said predetermined zone to bypass saidopposing voltage and permit said control voltage to operativelycondition said electron discharge device and cause it to conduct, andmeans responsive to the flow of current in said electron dischargedevice for changing said control voltage applied to said relay devicewhereby said relay device is actuated to perform said control function.

5. An electrical control circuit in accordance with claim 4 includingtime delay means comprising an RC. circuit associated with saidphotoelectric control means for providing a timed interval between theresponse of said photoelectric control means to the absence of saidadvancing strand of textile material and the operative conditioning ofsaid electron discharge device by said control voltage.

6. An electrical control circuit for a stop motion device comprising, incombination, an electrically operated relay device for performing acontrol function, an electron discharge device for controlling theactuation of said relay device, means for producing a predeterminedcontrol voltage for opcratively conditioning said electron dischargedevice and said relay device, and means including photoelectric controlmeans in said control circuit and being responsive to the presence of anadvancing strand of textile material in a predetermined zone, saidphotoelectric control means including means for providing a source ofA.C. voltage during the presence of said strand in said prcdeterminedzone and means for rectifying said A.C. voltage to provide a D.C.voltage of opposite polarity from said control Voltage for opposing thecontrol voltage applied to said electron discharge device forsufiiciently reducing the control voltage applied to said electrondischarge device to render said relay device inactive whereby absence ofsaid strand from said predetermined zone permits an increase in saidcontrol voltage to thereby operatively condition said electron dischargedevice and actuate said relay device to thereby perform said controlfunction.

7. An electrical control circuit for a stop motion device in accordanceWith claim 6 Wherein said electron discharge device includes atransistor having a base, means for applying said control voltage andsaid D.C. voltage to said base, and wherein said photoelectric controlmeans includes a phototransistor connected to said source of A.C.voltage, said phototransistor being arranged to conduct when said strandis absent from said predetermined zone to eliminate said D.C. voltagefrom said base and permit said transistor to conduct.

8. An electrical control circuit in accordance with claim 6 wherein saidrectifying means include a Voltage dou-bling circuit.

9. An electrical control circuit in accordance With claim 6 Wherein theirregularities in the diameter of said strand and normal oscillations ofsaid strand in said predetermined zone cause said A.C. voltage.

10. An electrical control circuit for a stop motion device in accordancewith claim 6 Wherein said control voltage contains an A.C. component toprovide a source of A.C. voltage.

11. An electrical control, circuit for a stop motion device comprising,in combination, an electron tube having a control grid, means connectedto said electron tube for initiating an interruption in the advance of astrand of textile material when said electron tube is conductive,

means for producing a control voltage having an A.C.l

component, means for applying said control voltage to said grid forpreventing ignition of said electron tube, a transistor having itscollector connected to said control grid and being so arranged that acurrent fiow in said transistor causes a voltage drop in said controlvoltage and permits said electron tube to ignite, means for applyingsaid control voltage to the base of said transistor to produce a currentfioW in said transistor, means for rectifying the A.C. component of saidcontrol voltage to produce an opposing voltage of opposite polarity fromthe control voltage applied to said transistor base and combinedtherewith to maintain said transistor in a non-conductive condition, aphototransistor, a light source operatively associated with saidphototransistor for defining a strand control zone, said phototransistorbeing arranged to produce a second A.C. voltage from the fluctuations inthe current flow through said phototransistor produced by theirregularities in the strand diameter and oscillations of said strandadvancing through said strand control zone, said second A.C. voltagebeing also rectified by said rectifying means together With said controlvoltage A.C. component and applied to said transistor base, saidphototransistor being arranged to conduct in the absence of said strandfrom said strand control zone and eliminate said A.C. voltage to permitsaid transistor to conduct and produce ignition of said electron tube.

12. An electrical control circuit for a stopv motion device comprising,in combination, an electron tube having a control grid, means connectedto said electron tube for initiating an interruption in the advance of astrand of textile material When said electron tube is conductive, meansfor producing a control voltage, means for applying said control voltageto said control grid while preventing ignition of said electron tube,means for producing an opposing voltage of opposite polarity from thecontrol voltage and being arranged in series with said means forproducing said control voltage, said last-named means including arectifier and a photoelectric device, a light source operativelyassociated With said photoelectric device for defiuing a strand controlzone, said photoelectric device being arranged to permit said rectifierand rectify said opposing voltage to maintain a negative bias on saidcontrol grid While said strand is interrupting light from said source tosaid photoelectric device Whereby, in the absence of said strand fromsaid strand control zone, said opposing voltage of opposite polarity iseliminated to permit an increase in the voltage in said control grid tocause ignition of said electron tube for initiating an interruption inthe advance of the strand.

References Cited in the file of this patent UNITED STATES PATENTS1,964,874 Fankboner July 3, 1934 2,438,365 Hepp et al. Mar. 23, 19482,486,334 Slamar Oct. 25, 1949 2,916,633 Stone et al. Dec. 8, 1959'UNITED s'rATEs PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,043,99l July 10, 1962 Henri W. Schneider' et al.

Column 10, line 40, for "and" read to Signed and sealed this 5th day ofMarch 1963.

(SEAL) Auest:

ESTON G. JOHNSON DAVID L. LADD Attesting Officer Commissioner of Patcnts

